<p><b>Abstract</b>—We argue that for a method to be useful in practice, it is necessary to perform its sensitivity analysis and to investigate its robustness to measurement errors. We present here a complete sensitivity analysis of the 3D reconstruction method based on projective geometry. We use this sensitivity analysis to best design a system for the inference of the shape of a block of granite from cameras placed at 90 degrees angular separation. The system has been tested on both real and synthetic data.</p>